Dialkyl dihydrothienyl phosphates

ABSTRACT

WHEREIN R and R1 and alkyl of 1 to 4 carbon atoms, R2 is hydrogen, halogen of atomic number 17 to 35 or alkyl of one to three carbon atoms and R3, R4 and R5 are hydrogen or alkyl or one to three carbon atoms and n is 0, 1 or 2. These phosphates are insecticidal.   Compound of the formula:

United States Patent 1 June 20, 1972 Stevick [54] DIALKYL DIHYDROTHIENYL PHOSPHATES [72] Inventor: Lawrence E. Stevick, San Francisco, Calif.

[73] Assignee: Chevron Research Company, San Francisco, Calif.

[22] Filed: Dec. 15, 1969 [21] Appl. No.: 885,291

[52] US. Cl. ..260/329 P, 260/3321, 260/3322 C, 260/3323 R, 260/332.5, 424/275 [51] lnt.Cl. ..C07d 63/08 [58] Field ofSearch ..260/329 P, 332.1, 332.5

[56] References Cited UNITED STATES PATENTS 3,106,565 10/1963 Newallis ..260/332.1 3,475,452 10/1969 3,205,238 9/l965 3,341,553 9/1967 3,234,238 2/1966 Weil et a1 ..260/329 2/1966 Greenbaum ..260/329 3,228,965 1/1966 Greenbaum et al. ..260/332.l

Primary Examiner-Henry R. Jiles Assistant Examiner-Cecilia M. Shurko Attorney-J. A. Buchanan, J r., G. F. Magdeburger, .lohn Stoner, J r., and Raymond Awyang [57] ABSTRACT Compound of the formula:

wherein R and R and alkyl of 1 to 4 carbon atoms, R-' is hydrogen, halogen of atomic number 17 to 35 or alkyl of one to three carbon atoms and R, R and R are hydrogen or alkyl or one to three carbon atoms and n is 0, l or 2. These phosphates are insecticidal.

7 Claims, No Drawings DIALKYL DIHYDROTI'IIENYL Pl-IOSPI-IATES FIELD OF INVENTION This invention is directed to novel dihydrothienyl phosphates and their use as pesticides. More specifically, it concerns 2,3-dihydrothien-4-yl phosphates and their use as insecticides.

DESCRIPTION OF INVENTION The compounds of this invention are dialkyl 2,3- dihydrothien-4-yl phosphates in which the alkyls are individually of one to four carbon atoms and the dihydrothienyl group is optionally substituted in positions 2 and 3 by alkyl of one to three carbon atoms and in position 5 by alkyl of one to three carbon atoms or halogen of atomic number 17 to 35, i.e., chlorine or bromine. These phosphates may be represented by the formula wherein R and R are alkyl of one to four carbon atoms each, R is hydrogen, alkyl of one to three carbon atoms or halogen of atomic number 17 to 35, R, R and R are hydrogen or alkyl of one to three carbon atoms and n is O, 1 or 2. The alkyl groups represented by R, R, R R, R and R which contain more than two carbon atoms may be straight chained or branched. Preferred compounds are those wherein n is 0, R R, R" and R are hydrogen and R and R are the same and are methyl or ethyl.

The dihydrothienyl phosphates of formula (1) above may be prepared by reacting a 2-halo-tetrahydrothiophen-3-one with a trialkyl phosphite. The l-oxo and 1,1-dioxo compounds (where n represents 1 or 2) may be prepared by oxidizing the product of the tetrahydrothiophen-3-one/phosphite reaction. The phosphite/tetrahydrothiophen-3-one reaction may be represented by the following equation:

wherein X is halogen of atomic number 17 to 35, R is alkyl of l to 4 carbon atoms and R, R, R, R, R and R are as defined previously. This reaction is preferably carried out in an organic liquid diluent which does not react with the starting materials under the reaction conditions. Preferred among such diluents are aromatic hydrocarbons such as benzene, toluene and xylene.

The reaction temperature will normally be in the range of about l0 to +130 C. For convenience reflux temperature may be used. The reaction pressure is not critical and subor superatmospheric pressures may be used if desired. Atmospheric or autogenous pressure will usually be employed.

The 2-halo-tetrahydrothiophen-3-one reactant may be prepared by halogenating the corresponding tetrahydrothiophen-Ii-one with a mild halogenating agent such as sulfuryl chloride in the presence of a substantially non-polar organic solvent. The chlorination may also be effected with molecular chlorine. I-Ialogenation temperatures will usually be in the range of 40 to +20 C. Depending on the extent of halogenation, either one or two halogens will be added to the 2-position. The extent of halogenation is determined by the relative concentration of the two reactants as well as the time and temperature of reaction.

Tetrahydrothiophen-3-one and the alkyl substituted tetrahydrothiophen-Zi-ones required in the above described halogenation reaction may be prepared by the well known Dieckmann condensation of an a, fi-dicarbalkoxydialkyl sulfide, Organic Reactions, Vol. XV, Ed. by R. Adams et al., published by J. Wiley and Sons, Inc., New York, 1967, pages 14, 17-18, 123-129, and Journal of the American Chemical Society, Vol. 68, pages 2,229-2,235 (1946). In this reaction, a suitably substituted 0:, B'-diester dialkyl sulfide is cyclized to form a 2- and/or 4-carbalkoxy tetrahydrothiophen-3-one which is converted to the corresponding tetrahydrothiophen- 3-one by hydrolysis and decarboxylation.

Cyclization of the a, B'-dicarbalkoxydialkyl sulfides is accomplished by heating the diester under anhydrous conditions in the presence of a base catalyst. Satisfactory catalysts for this reaction include the alkali metal alkoxides, hydridcs, and amides. The preferred catalyst is sodium alkoxide in which the alkoxide corresponds to the alcohol portions of the diester. In particular the cyclization of a, [3'-carbomethoxydialkyl sulfide in the presence of sodium methoxide is especially preferred.

This cyclization reaction may be carried out in the absence of any solvent or preferably in an inert aprotic solvent such as toluene, benzene, xylene, tetrahydrofuran, diethyl ether and dimethyl sulfoxide. The temperature of the reaction is frequently at the boiling point of the solvent; and may be within the range of 15 to 150 C. Pressure is not critical, but the reaction is commonly run under atmospheric pressure at the reflux temperature of the solvent with constant removal of the by-product alcohol formed during reaction, thereby increasing the yield of cyclic ketone.

The cyclization reaction should be carried out in an inert, dry atmosphere. Dry, oxygen-free nitrogen is preferred. All traces of moisture and air should be removed from the reaction vessels before addition of the catalyst.

The hydrolysis and decarboxylation of the carbalkoxy group of a 2- and/or 4-carbalkoxy tetrahydrothiophen-B-one may be accomplished by heating this compound with water or aqueous alcohol and an acid at temperatures in the range of 65 to 150 C. Inorganic acids such as sulfuric, phosphoric or hydrochloric acid will normally be employed. Reaction times for hydrolysis and decarboxylation will usually be within the range of 2 to 20 hours.

The a, B-dicarbalkoxydialkyl sulfide used in the cyclization reaction may be obtained by the addition of an ester of thioglycolic or substituted thioglycolic acid to an ester of a, B- unsaturated acid such as acrylic acid, methacrylic acid or crotonic acid. This addition reaction is also base catalyzed. Satisfactory catalysts include the organic amines such as piperidine, morpholine, etc., as well as the stronger alkali metal catalysts listed above for the cyclization reaction. The reaction may be carried out with or without a solvent. The organic bases are preferred in a solvent free process. Typical solvents for this reaction include those previously listed for the cyclization reaction. The addition reaction takes place at temperatures in the range of 0 to 50 C., and reaction times are generally in the range of 10 to minutes. In order to minimize competing side reactions the unsaturated ester is preferably added to the thioglycolate-catalyst mixture. One convenient and preferred method of carrying out the preparation of the cyclic ester intermediates of this invention involves a sodium thioglycolate catalyzed addition of a thioglycolate to a linear, unsaturated ester in a solvent such as dimethylsulfoxide followed by cyclization without separation and purification of the a, B'-dicarbalkoxydialkyl sulfide. In this in situ method of cyclic ester preparation, the temperature is maintained on the low side, i.e., about 0 to 10 C. during sulfide preparation, and is then raised to higher temperatures to cause cyclization.

Oxidation of the heterocyclic sulfur atom in the tetrahydrothiophen-3-one ring to form the l-oxo (sulfoxide) and the 1,1-dioxo (sulfone) derivatives may be accomplished by reacting the phosphate product of the above formula (1) 65.4 g. of tetrahydrothiophen-3-one was collected at 6365 C. This material appeared as a water-white liquid.

Of the tetrahydrothiophen-3-one prepared above, 20.4 g. was mixed with 100 cc. of toluene in a vessel. To this was with suitable oxidizing agents such as hydrogen peroxide or added dropwise 27.0 g. of sulfuryl chloride over a period of 20 organic peracids such as perbenzoic, perphthalic, mminutes at 20 to 30 C. with dry nitrogen being introduced chloroperbenzoic and peracetic. The amount of oxidizing vigorously into the mixture. When addition was comple agent employed is generally in the range of 90 to l percent nitrogen flow was continued for 45 minutes as the temperaof theoretical, i.e., for each mole of sulfide, from 0.9 to 1.1 ture was allowed to rise to 10 C. A vacuum was drawn on moles of oxidizing agent is used for conversion to the sulfoxide the mixture for 10 minutes at approximately .5 C. (The color derivative and more than 1.8 moles, preferably over 2.0 moles of the mixture turned very pale clear blue at this higher temof oxidizing agent, is used for conversion to the sulfone derivaperature.) This cool mixture was added rapidly to 49.8 g. of tive. This reaction is exothermic and the oxidizing agent is 'triethylphosphite in 150 cc. of benzene at reflux temperature. preferably added slowly or in small increments while main- The color of the combined mixture immediately became pale taining the temperature in the range of 0 to 50 C., preferably yellow. It was stirred for 1 hour at reflux temperature (approx- 15 to C. Oxidatively stable solvents may be employed in imately 90 C.) with repeated checks by gas liquid chromatogthis reaction.v Suitable solvents include the chlorinated raphy to detennine the progress of the reaction. After the hydrocarbons such as dichloromethane, chlorobenzene, and above-mentioned 1 hour period the mixture was stripped the like. under vacuum at 80 C. In this way, 47.6 g. of diethyl-2,3-

The following table lists representative phosphates of for- 20 dihydrothien-4-yl phosphate was thus recovered as a clear mula (l) and the reactants which may be used to prepare bright red oil. The infrared spectrum and gas liquid chromatothese phosphates. graphic analyses of this product indicated that the phosphate TABLE I I V r Reactants Tetrahydrothiophehone Phosphite Dihydrothicnyl phosphate product 2- 11 r -tetrah drothio hen-3one 'li'ibutyl phosphite Dibutyl 2.3 dihydrothien-4-y1 phosphate. 221i]grg4j-dici hyltetnfiiydrothiophen-Elone Trimethylph0sphit0. Dimethyl2,3-d1ethyl-2,3-d1hydroth1cn-4-yl phosphate. lie]1loro-l-pmpyltctl'uhyd1'othi0phtu3-0l10 'Iripropylpl10spl1it0. D propyl 3-D1'0pyl-5-chlor0-2,3{l1l1ydr0th1en-4-yl phosphate.

libromotutmhydrothiophei1-3one 'lrietllyl phosplnte iethyl 5-b101no-2 3-dihydrotluen-4-yl phosphate. g-broi1io-5-vtliyltvtmllydrothiophvn-Zi-ox1e 'lrimtthyl pliosphitt n. Duuethyl Q-ethyl:2,3-d1hydrothlenA-yl phosphate. 2-vhloro-l,fi-dimuthyltutmliydrotlnophvn-Ii-ouv 'lriisopropyl phosplutcn l) us0p 0Dy 2,3-dnnethy1-2,3-d111ydroth1en-4-yl phosphate. LZ-diuhlom-l-xnothyl-5-ctliyltvtmhydrothiophcu-3-ou0. Trimethyl phosplute. bulnetthyl2-ethy1-3-1net11y1-5-chloi'o-2,3-dihydrotluen-i-ylphos p 10. G. l,B-dichloro-l-vl.hyl-fi-isopi'opytotmhydrothiophcn-B-ouc Triethyl phosphito DieIthLyI 2-isopropy1-3-ethy1-5-c11101'0-2,3-di11yd1'ot11ieiH-y1 phosl.) 13. 0. t 2,2- 1 --l.5- 1i nttli 'ltct.ruhydroiliio 110118-0111 Tripropyl pl1osphitc. Dipi'opyl 2,3-dimetliyl-5-b1o1no-2 B-dihydrothieuA-yl phosphate. w 1SL382 fi-triiniwhylivtmliydi'othioplibn-lroiu Trimcthyl phosphitenu Dimethyl 2,2 ,3-t111118t11371-2341111ll'0tlllQl1:1-yl phosphate. 24mm, 0 intothvl-5-vthyltotrnhydrothioplwn-is-onu. Triethyl phosphitc Dretliyl 2,3-d1methyl-2et11yl2,3-d1hydrotlnen-l-yl phosphate. 2-t-111om- -propyltvti-ul1ydrothiomien-3on0 Trinwtliyl phosphitv 1methy15-propyld.3-dihydrotluen-i-yl phosphate. .Z-brmno-B-mvthyI-LS-diethyltetrahydrothiophon one 'Iriethyl phosplnte... D ethyl 2, 3-diethyl-5-metl1yl-2,3- 11hydrotl11en4-y1 phosphate. .Z-ch1oro-2-ct11yl-i-isopropyltctrahydrothiophmr-S-one Tributyl phosphite Diethyl 21sopropy1-5-ethyl-LZ,3-dihydrothien-1-yl phosphate.

EXAMPLES was contaminated with minor amounts of starting materials.

The following examples illustrate the methods which may be used to prepare the tetrahydrothiophen-3-one, the halotetrahydrothiophen-B-one reactants described above and the phosphates of this invention. These examples are intended as illustrativeonly and are not meant to limit the invention described herein in any manner. Unless otherwise indicated, percentages are by weight.

Example 1 Preparation of diethyl 2,3-dihydrothien-4-yl phosphate Sodium. 46.0 g. was dissolved in 800 cc. of methanol in a vessel. 212.2 g. of methyl a-mercaptoacetate were added to that solution. The combined mixture was stirred at 50 C. for minutes. The reaction mixture was then stripped under vacuum leaving a yellow solid which was dissolved in 1 liter of dimethyl sulfoxide. This sulfoxide solution was cooled to 10 C. and 198.0 g. of methyl acrylate were added dropwise to it at 10 to 12 C. over a 30 minute period. After this addition, the mixture was stirred at 12 to 20 C. for l hour. The mixture was'then poured into 1,500 cc. of ice water and 200 cc. concentrated HCl. It was extracted twice with 1 liter portions of ether. The combined ether extracts were washed with 600 cc. of ice water and dried overnight with MgSO The combined extracts were filtered and the ether was stripped off under vacuum leaving 307 g. of crude 2-carbomethoxy tetrahydrothiophen-3-one as a clear yellow oil.

The crude 2-carbomethoxy tetrahydrothiophen-Ii-one prepared above,160 g.,was mixed with 500 g. of a 10 percent aqueous solution of H 50, in a vessel. This mixture was heated to reflux for 5 hours, followed by cooling to 10 C. The reaction mixture was extracted twice with 500 cc. portions of ether. The combined ether extracts were dried over MgSO and then filtered. The ether was stripped at 30 C. under vacuum. The crude reaction mixture was then distilled and Analysis of this crude product was as follows: Calculated for C H OPS: P, 12.98; S, 13.48;Found: P, 13.38; S, 13.87. Example 2 Preparation of dimethyl 5'chloro-2,3- dihydrothien-4-yl phosphate A reaction vessel was charged with 50 ml. of sulfuryl chloride which was cooled to 0 C. Then while vigorously passing nitrogen through the sulfuryl chloride, 10.2 g. of tetrahydrothiophen-B-one was added dropwise over a period of about 10 minutes. The reaction mixture was stirred for 5 more minutes and then ml. of toluene was added. Stirring was continued for 1 hour during which time the temperature rose to 23 C. At the end of this time the excess sulfuryl chloride was removed by evaporation at 30 C. under a vacuum to give a red toluene solution of 2,2- diehlorotetrahydrothiophen-3-one.

The above described toluene solution was added rapidly to a refluxing solution of 18.6 g. of trimethyl phosphite in 50 ml. of toluene. Afier addition was complete the reaction mixture was stirred for 1% hours at the reflux temperature,. cooled somewhat and treated with charcoal. After filtration, the toluene solvent was removed by heating at 60 C. under vacuum. In this way there was obtained 23 g. of crude product. A 16 g. portion was distilled to give dimethyl 5- chloro-2,3-dihydrothien-4-yl phosphate, b.p.- 122 C. at 0.1 mm Hg. Analysis gave the following results: Calculated for C H ClOJS: Cl, 14.50; P, 12.63; S, 13.10; Found: C], 14.20; P, 12.50; S, 13.03. Example 3 Preparation of dimethyl dihydrothien-4-yl phosphate 3-methyl tetrahydrothiophen-4-one was prepared from methyl thioglycolate and methyl methacrylate by essentially the same process as described in Example 1. This ketone, 1 1.6 g. was dissolved in 100 m1. of toluene and cooled to 20 C.

3-methy1-2,3-

Then, while passing nitrogen through the solution and keeping the temperature in the range of 20 to 30 C., 13.5 g. of sulfuryl chloride was added rapidly. Five minutes after the addition was complete, the solution was placed under vacuum and the temperature was slowly raised to C. At this temperature, the vacuum was released and 18.6 g. of trimethyl phosphite was added and the temperature was rapidly raised to the reflux. Heating was continued at the reflux for 3 hours. Then the toluene solvent was removed by heating at 70 C. under a vacuum. In this way there was obtained 19.5 g. of crude phosphate product.

The crude product was then charged to a silica gel chromatographic column and washed with a 2:1 hexanezether solution to remove impurities. When this solvent system failed to remove any more material from the column, the desired product was eluted from the column using a 1:1 hexanezether mixture. in this way there was obtained 8.1 g. of dimethyl 3- methyl-2,3-dihydrothien-4-yl phosphate, which analyzed as follows. Calculated for C7H13O4PS: P, 13.78; S, 14.30; Found: P, 13.81;S, 14.24.

Example 4 Preparation of dimethyl l,l-dioxo--chloro-2,3- dihydrothien-4-yl phosphate The product of Example 2, 8.1 g., was dissolved in 150 ml. of dichloromethane. Then 14.5 g. of 85 percent m-chloroperbenzoic acid was added in small increments over a period of 1 hour. When addition was complete, the reaction mixture was stirred for 16 hours at 23 C. At the end of this time, the mixture was filtered, washed with aqueous sodium bicarbonate (20 g. in 400 ml. water), and with water. It was then dried over anhydrous magnesium sulfate. After filtering and evaporation of the solvent, there was obtained 6.0 g. of product. Analysis was as follows: Calculated for C H CIO PS: Cl, 12.81; P, 11.18; S, 11.60; Found: C1, 12.98;P, 10.90; S, 11.49.

Example 5 Preparation of diethyl l-oxo-5-chloro-2,3- dihydrothien-4-yl phosphate Diethyl 5-chloro-2,3-dihydrothien-4-yl phosphate was prepared by essentially the same process as in Example 2 using triethyl phosphite in place of trimethyl phosphite. A flask was charged with 22.0 g. of diethyl 5-chloro-2,3dihydrothien-4-yl phosphate and 150 ml. of dichloromethane. To this solution there was added 16.2 g. of 85 percent m-chloroperbenzoic acid in increments over a period of minutes. After all the acid was added, the solution was stirred for 30 minutes at 0 C., and at 23 C. for 4 hours. At the end of this time the reaction mixture was filtered and diluted with an equal volume of diethyl ether. The resulting solution was washed with 10 percent sodium carbonate and with ice water. It was dried over magnesium sulfate. After filtration and solvent removal there was obtained g. of product. Analysis was as follows: Calculated for C H ClO PS: Cl, 12.30; P, 10.70; S, 11.1 1; Found: Cl, 1 1.62; P, 10.58; S, 10.62

Using the above described procedures. other dihydrothienyl phosphates and oxidized dihydrothienyl phosphates were prepared. These phosphates, along with their analyses, are reported in Table 11.

TABLE 11 Representative phosphates of this invention were tested by the following procedures to illustrate the insecticidal properties of the group. The test results are reported in Table III.

CONTACT TESTS German Cockroach (Blaltella germanica L): A 100 ppm. acetone solution of the candidate toxicant was placed in a microsprayer (atomizer). A random mixture of anesthetized male and female roaches was placed in a container and 55 mg. of the above described acetone solution was sprayed on them. A lid was placed on the container. A mortality reading was made after 24 hours.

Houseflies (Musca domestica): A 250 ppm. acetone solution of the candidate toxicant was placed in a syringe. A random mixture of anesthetized male and female DDT-resistant houseflies was placed on cardboard squares. A 0.5 microgram dose of the acetone solution was applied directly to each fly. The flies were then placed in a recovery cage. Mortality readings were taken after 24 hours.

Aphids (Aphids gossypii Glover): An acetone solution of the test compound was prepared and diluted with water containing a small amount of nonionic surfactant to 30 ppm. 3 replicate cucumber leaf sections each infested with at least 20 aphids were dipped into this acetone-water solution. Excess solution was drained from the section and they were held under controlled conditions for 24 hours. Mortality readings were then made on 20 randomly selected aphids per replicate and the percent mortality based on the average of these readings was calculated.

Mites (Telranychus telarius L): An acetone solution of the test compound was prepared and diluted with water containing a small amount of nonionic surfactant to 100 ppm. 3 replicate lima bean leaf sections each infested with at least 20 mites were dipped into this acetone-water solution. Excess solution was drained from the section and they were held under controlled conditions for 24 hours. Mortality readings were then made on 20 randomly selected mites per replicate and the percent mortality based on the average of these readings was calculated.

SYSTEMIC TESTS Aphids (Aphids gossypii Glover) and Mites (Tetranychus telarium L): An acetone solution of the test compound (with a small amount of nonionic surfactant added) was prepared and diluted with water to 500 ppm. 40 ml. of this solution was applied to the soil in a 4 inch pot containing two plants (pinto bean for mites; cucumber for aphids). Forty-eight hours after this application these plants were infested with the test insects. Mortality readings were taken 48 hours after infestation and a percent mortality was calculated from these readings.

ln topical tests similar to those described above phosphates included within this invention exhibited control of milkweed bug, cabbage looper, mosquito larvae, dock beetle larvae and mite eggs.

Phosphates of this invention also have exhibited excellent Percent Element analyses Compound Dimathyl .2,3-dihydrothian-4-yl phosphate Diethyl 5-ch101'0-2,3-dihydrothien4-yl phosphate Diethyl 2-n1ethy1-2,3-dihyd1'0thien-4-yl phosphate Dimethyl 2-1nethy1-2,3-dihydrothienA-yl phosphatev Dimethyl 2-111ethyl-5-chl0ro-2,3-dihydrothien-4-yl phosphate Diethyl 1,l-dioito-ZB-dihhydrothielH-yl phosphate Dlethyl 1,l-dloxo-fi-chlol'o-12,3-di-hydrothien4-yl phosphate UTILITY The dihydrothienyl phosphates of this invention exhibit a wide spectrum of insecticidal activity in both topical as well as systemic applications. In such applications insecticidal quantities of one or more of these phosphates are applied directly to the insects or their environment.

Cale.

Cale.

Found Found TABLE III Percent mortullty Contact tests Systemic tests mp n Flies Aphids r0232: Mites Aphids Mites this invention may be applied in other liquid or solid formulations to the pests described above, their environment or hosts susceptible to attack from such pests. For example, when applied as insecticides they may be sprayed or otherwise applied directly to plants or soil so as to eflect control of insects coming into contact therewith. When used as nematocides, they will normally be applied directly to nematode-infested soil at dosage levels between 3 and 40 pounds per acre. (Solid formulations may be plowed into the soil; liquid formulations ma be sgrayed or ingected.)

orm atlons of t e compounds of tlus invention will comprise a toxic amount of one or more phosphates and a biologically inert carrier. Usually they will also contain a wetting agent to facilitate their penetration and dispersion into the soil and/or hosts to which they are applied. Solid carriers such as clay, talc, sawdust and the like may be used insuch formulations. Liquid diluents which may be used with these compounds include xylene, toluene, acetone and benzene.

The terms insecticide and insect" as used herein refer to their broad and commonly understood usage rather than to those creatures which in the strict biological sense are classified as insects. Thus, the term insect" is used not only to include small invertebrate animals belonging to the class Inseam but also to other related classes of arthropods whose members are segmented invertebrates having more or fewer than six legs, such as spiders, mites, ticks, centipedes, worms and the like.

As will be evident to those skilled in the art, various modifications on this invention can be made or followed, in the light of the foregoing disclosure and discussion, without departing from the spirit or scope of the disclosure or from the scope of the following claims.

I claim:

1. A compound of the formula:

wherein R and R are alkyl of one to four carbon atoms, R is hydrogen, alkyl of one to three carbon atoms or halogen of atomic number 17 to 35, R, R and R are hydrogen or alkyl of one to three carbon atoms and n is 0, l or 2.

2. The compound of claim 1 wherein said halogen is chlorine.

3. The compound of claim 1 wherein n is 0, R and R are the same and are methyl or ethyl, and R R, R and R are hydrogen.

4. The compound of claim 1 wherein n is 0, R and R are the same and are methyl or ethyl, R is chlorine, R is hydrogen or methyl, and R and R are hydrogen.

5. The compound of claim I wherein n is 2, R and R are the same and are methyl or ethyl, R is hydrogen or chlorine, and R, R and R are hydrogen.

6. The compound of claim 1 wherein Rand R are ethyl, n is l, R is chlorine and R", R and R are hydrogen.

7. The compound of claim 1 wherein R and R are the same and are methyl or ethyl, R R and R are hydrogen, R is methyl, and n is 0. 

2. The compound of claim 1 wherein said halogen is chlorine.
 3. The compound of claim 1 wherein n is 0, R and R1 are the same and are methyl or ethyl, and R2, R3, R4 and R5 are hydrogen.
 4. The compound of claim 1 wherein n is 0, R and R1 are the same and are methyl or ethyl, R2 is chlorine, R3 is hydrogen or methyl, and R4 and R5 are hydrogen.
 5. The compound of claim 1 wherein n is 2, R and R1 are the same and are methyl or ethyl, R2 is hydrogen or chlorine, and R3, R4 and R5 are hydrogen.
 6. The compound of claim 1 wherein R and R1 are ethyl, n is 1, R2 is chlorine and R3, R4 and R5 are hydrogen.
 7. The compound of claim 1 wherein R and R1 are the same and are methyl or ethyl, R2, R3 and R4 are hydrogen, R5 is methyl, and n is
 0. 